Fetch unknown collection when handling FeatureRequest activity (#38413)

spec/lib/activitypub/activity/feature_request_spec.rb

@@ -52,5 +52,28 @@ RSpec.describe ActivityPub::Activity::FeatureRequest do
           end, recipient.id, sender.inbox_url)
       end
     end
+
+    context 'when the collection is not yet known' do
+      let(:discoverable) { true }
+      let(:collection) { instance_double(Collection, uri: 'https://example.com/collections/1') }
+      let(:stubbed_service) do
+        service = instance_double(ActivityPub::FetchRemoteFeaturedCollectionService)
+        allow(service).to receive(:call) do
+          Fabricate(:remote_collection, account: sender, uri: collection.uri)
+        end
+        service
+      end
+
+      before do
+        allow(ActivityPub::FetchRemoteFeaturedCollectionService).to receive(:new).and_return(stubbed_service)
+      end
+
+      it 'fetches the collection before handling the request' do
+        subject.perform
+
+        expect(ActivityPub::DeliveryWorker).to have_enqueued_sidekiq_job
+        expect(stubbed_service).to have_received(:call)
+      end
+    end
   end
 end